Commercially available state of the art VCSELs suffer from too low power conversion efficiency so that competition with high power laser bars is difficult. Although the production costs for VCSEL arrays are relatively low, the fraction cost per output power is in tight competition with conventional light sources.
US 2011/0086452 A1 proposes a VCSEL with intracavity contacts to improve the efficiency of the laser. The provision of intracavity contacts allows realising the top and bottom DBR mirrors with an undoped layer structure minimizing free carrier absorption and trap related absorption in these mirrors. This reduction of absorption losses increases the efficiency of the laser. Doped current-injection layers are arranged between the DBRs and the active region and are contacted by appropriately arranged metallic contacts. The doping of the current-injection layers varies in the direction of the optical axis of the laser to form several highly doped regions between lower doped regions or regions without doping. The higher doped regions are arranged in minima of the standing electrical field of the laser radiation oscillating in the laser resonator. This reduces optical absorption losses caused by the doping of the current-injection layers. The top and bottom DBRs are formed of alternating layers of GaAs and AlGaAs. Alternatively alternating layers of GaAs and AlAs are proposed.